Data acquisition for modular biometric monitoring system

ABSTRACT

A modular system for acquiring biometric data includes a plurality of data acquisition modules configured to sample biometric data from at least one respective input channel at a data acquisition rate. A representation of the sampled biometric data is stored in memory of each of the plurality of data acquisition modules. A central control system is in communication with each of the plurality of data acquisition modules through a bus. The central control system is configured to collect data asynchronously, via the bus, from the memory of the plurality of data acquisition modules according to a relative fullness of the memory of the plurality of data acquisition modules.

RELATED APPLICATION

This application relates to U.S. patent application Ser. No. 11/236,899,which was filed on Sep. 28, 2005, and entitled COMPACT WIRELESSBIOMETRIC MONITORING AND REAL TIME PROCESSING SYSTEM, the entirecontents of which application is incorporated herein by reference.

GOVERNMENT INTEREST

The subject innovation is being developed with government support underContract No. NNC05CA65C awarded by NASA. The United States governmentmay have certain rights in the invention.

BACKGROUND

Diagnosis of ailments and treatment of disease often requires ananalysis of biological signs obtained from a patient in the course ofnormal activity over a period of time. Personal health monitors arecommonly employed to gather data related to a patients biometric data.

In general, a personal health monitor is a device used to measure andrecord one or more clinical parameters of a patient for latertransmission to the patient's physician or other health care provider.The personal health monitor may be used in a hospital or clinicalsetting as an adjunct to existing care. Additionally, the personalhealth monitor may also be used by the patient outside care facilities(e.g., at a patient's home). When used by a patient at home, the patientoperates the personal health monitor to record certain bodily clinicalparameters. The personal health monitor can be used by the patient whohas a condition requiring monitoring of one or more clinical parameters,but who otherwise may not require the level of care such as provided bya hospital. Accordingly, the personal health monitor provides potentialsavings in medical costs involved with a hospital stay.

For example, continuously monitoring cardiac patients immediatelyfollowing coronary attacks is important. Such is normally accomplishedeffectively in the coronary care unit of most hospitals where thepatients are continuously monitored following heart attacks to detectarrhythmias of the heart, for example monitoring and warning forventricular arrhythmias, which may lead to ventricular fibrillation anddeath. Through prompt recognition and treatment of such warnings relatedto ventricular arrhythmias in coronary care units, the mortality rate ofacute myocardial infarctions has been reduced considerably. In addition,many post myocardial infarction cardiac patients continue have frequentventricular extra systoles after discharge from the hospital.Accordingly, it is desired to continuously monitor the patient over acertain period of time and under varying conditions of stress, todetermine the effectiveness treatment which has been introduced, such asthe proper dosage of medication.

Constant monitoring of such patients after release from the hospital maybe difficult because of the logistics involved, and particularly sincethey can no longer be monitored closely as a group by direct wiring orclose telemetry, as commonly implemented in hospital settings. As aresult, various systems have been developed to attempt to monitor theECG signals of out-patients to thereby provide a diagnostic tool foradditional treatment or variation of treatment for the patients as maybe required.

Nevertheless, many such mobile units are typically spacious anddifficult to set up and maintain. Moreover, in general these units arenot suitable for readily monitoring a plurality of biological conditionsand indicators useful for many situations. In addition, such systemslack flexibility during usage as they typically have fixed sensor typesand configurations.

SUMMARY

The invention relates to systems and methods for collecting data from aplurality of data acquisition modules. For example, the approachdescribed herein enables data to be acquired at one or more modulessynchronously and to be collected from such module(s) by a centralcontrol asynchronously, such as based on relative fullness of memory atthe one or more modules.

One aspect of the invention relates to a modular system for acquiringbiometric data. The system includes a plurality of data acquisitionmodules configured to sample biometric data from at least one respectiveinput channel at a data acquisition rate. A representation of thesampled biometric data is stored in memory of each of the plurality ofdata acquisition modules. A central control system is in communicationwith each of the plurality of data acquisition modules through a bus.The central control system is configured to collect data asynchronously,via the bus, from the memory of the plurality of data acquisitionmodules according to a relative fullness of the memory of the pluralityof data acquisition modules.

Another aspect of the invention relates to a biometric monitoring systemthat includes a plurality of modular components configured to samplebiometric data received from at least one respective input channelaccording to a data acquisition rate. Each of the plurality of modularcomponents includes a first memory structure for storing housekeepinginformation associated with operation of the modular component. Each ofthe plurality of modular components also includes a second memorystructure for storing a representation of the sampled biometric data.The housekeeping information in the first memory structure is updated inresponse to storing the representation of the sampled biometric data inthe second memory structure. A master module is configured to retrievedata asynchronously, via a bus to which each of the plurality modularcomponents is connected, from the second memory of the plurality modularcomponents according to a relative fullness of the second memorystructure in each of the plurality modular components as determined bythe master module based on the updated housekeeping information in theplurality of modular components.

Still another aspect of the invention relates to a method for acquiringbiometric data. The method includes sampling biometric data for each ofthe plurality of modular components at a substantially synchronous dataacquisition rate and storing the sampled biometric data in a firstmemory structure of each of the respective plurality of modularcomponents. A counter in a second memory structure of each of theplurality of modular components is updated in response to the storing ofthe sampled biometric data. A fullness of the first memory structure ineach of the plurality of modular components is determined based at leastin part on the updated counter in the second memory structure of eachrespective modular component and biometric data is retrieved from atleast one of the plurality of modular components in response to thedetermined fullness of the first memory structure in the at least one ofthe plurality of modular components.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an example of a biometric monitoring system that can beimplemented according to an aspect of the invention.

FIG. 2 depicts an example of a modular component that can be implementedin a biometric monitoring system according to an aspect of theinvention.

FIG. 3 depicts an example of a master module that can be implemented ina biometric monitoring system according to an aspect of the invention.

FIG. 4 depicts an example of a modular system that can be implementedaccording to an aspect of the present invention.

FIG. 5 depicts another example of a modular system that can beimplemented according to an aspect of the present invention.

FIG. 6 is a flow diagram illustrating a method that can be utilized tocollect data in a biometric monitoring system according to an aspect ofthe invention.

FIG. 7 is a flow diagram illustrating a method that can be utilizedacquiring data as well as for communicating data in a biometricmonitoring system according to an aspect of the invention.

DETAILED DESCRIPTION

The subject innovation relates to systems and methods to perform dataacquisition in a modular system. For example, the approach describedherein enables data to be acquired at one or more modules synchronouslyand to be collected from such module(s) by a central controlasynchronously, such as based on relative fullness of memory at the oneor more modules.

FIG. 1 depicts an example of a system 10 that can be utilized to acquirebiometric data. As used herein, the term “biometric data” or relatedphrases (e.g., “biometric parameter” and “biometric information”) isintended to encompass biological or biomedical information, such as maybe acquired from one or more sensors. Biometric data can also relate toinformation associated with controlling or monitoring the delivery of atherapy being delivered to a patient or it can also representinformation associated with controlling drug delivery equipment orsensor equipment or operating parameters associated with sensor statusand operation that may be employed in connection with the acquisition ofdata or control of therapy devices.

The system 10 includes a plurality of modules, which are also referredto herein as modular components. In the example of FIG. 1, the system 10includes a master module 12 and a plurality of other modular components14, 16, 18, 20, 22 and 24. Each of the respective modular components12-24 can be programmed and/or configured according to the intended useof the system 10. At least some of modular components 14, 16, 18, 20, 22and 24 can be replaced, inserted and/or swapped to achieve a desiredaggregate function, such as can include collection of biometricparameters, control delivery of a desired therapy, communication of datato and from the system 10 or any combination thereof.

For example, a clinician can determine a customized routine foracquisition of biometric data and or therapy. Based on the routine, theclinician can determine which types of modules should be inserted intothe system as the modular components 12-24. For instance, the modularcomponents 14 and 16 can be configured to acquire biometric dataassociated with a patient and the modular component 18 can deliver adesired type of therapy (e.g., electrical and/or chemical) to a patient.

By way of further example, the modular component 14 can measure one ormore biometric parameters, and/or supply input that is representative ofthe status of a controlled process. The input can be provided to themaster module 12 or another modular component 18, such as can beconfigured to change one or more outputs for effecting control of thetherapy process. For instance, one or more of the modular components 12,14 and 16 can supply activation commands to a glucose pump in apatient's proximity, such as when acquired data that pertains to bloodsugar of a patient indicates a critical level. Similarly, muscle tensioncan be employed as a biometric condition to be collected by a modularcomponent, and employed for delivery of chemical or electrical therapyto perform muscle relaxation by the same or a different modularcomponent to a patient. The inputs and outputs of each of the modularcomponent 12-24 can be binary, (e.g., on or off), and/or analog assuminga continuous range of values.

Each of the respective modular components 12-24 can communicate over adata bus or backplane 26. For example, the bus 26 can enablecommunication between the master module 12 and any of the other modularcomponents 14-24. Additionally or alternatively, each of the modules12-24 can communicate with each other over the bus 26. Those skilled inthe art will understand and appreciate various types of buses orcommunication links and communications protocols that can be utilized toprovide for communication between the respective modules 12-24.

As a further example, each of the modular components 14-24 can beconnected to the bus via a physical interface (e.g., a slot having agiven form factor) having a predetermined physical address location incommunication with the bus 26. The master module 12 can thus communicatewith each module using this physical address, such as part of aconfiguration mode in which the master module 12 acquires information(e.g., hardware configuration) about each modular component 14-24 thatis connected to the bus 26. The master module 12 can also assign eachother modular component 14-24 a respective address that can be utilizedto facilitate subsequent communication with the modular components overthe bus 26, such as for sending requests and responses during normaloperation.

The system 10 can be considered a distributed computing arrangementsince certain processing functions can be distributed to the respectivemodules 14-24. In this way, computing power requirements of the mastermodule 12 can be reduced based upon the portions of processing beingimplemented at the respective components 14-24. In this respect, thepower usage of the system 10 can be scaled to the medically desiredconfiguration of the system. By way of further example, each of themodules 14, 16 and 18 can correspond to a modular apparatus that can beutilized to acquire biometric data that can be transmitted to the mastermodule 12 for aggregate communication to one or more remote clients,such as a Personal Digital Assistant (PDA), computer, workstation, aserver and the like.

In the example of FIG. 1, the master module 12 can include a buscontroller 30 that can be utilized to control data communication overthe bus 26. For instance, the bus controller 30 can transmit data (e.g.,in the form of data requests) from the master module 12 to therespective modular components 14 through 24 via the bus 26, such asmentioned above. As one example, the master module 12 can providerespective program instructions to one or more of the modules 14 through24 for controlling operation and the particular function being performedby the respective module(s). This can include setting one or moreoperating parameters sampling rates, configuration settings as well asdefining the specific functions or tasks being performed by therespective components. The bus controller 30 can also be configured tocontrol how and when each of the respective modules communicates dataover the bus 26.

The master module 12 also includes a processor 32 that can executeprogram instructions stored in associated memory 34. The memory 34 canbe implemented as including one or more different types of memory, suchas volatile or nonvolatile memory. The memory 34 can be accessed by theprocessor 32 for storing executable instructions for controllingoperation of the master module 12 and the system 10, more generally. Thememory 34 can also be utilized to store data that is provided to themaster module via the transceiver 36 or bus controller 30. For example,the memory 34 can be employed as a temporary data storage device forbiometric data and control information that may be received from any ofthe other respective modules 14 through 24 via the bus 26.

According to one aspect of the invention, the memory 34 can storeexecutable instructions that control high level functions of the buscontroller 30 to facilitate and optimize traffic over the bus 26. Forexample, the processor 32 can control the bus controller 30 to collectdata from each of the respective modules 14-18 asynchronously accordingto a relative fullness of memory in each of the respective modules. Themaster module 12 can determine the relative fullness of the modules inresponse to requesting certain housekeeping information from themodules. For instance, certain housekeeping information (e.g.,corresponding to the type of module, sampling rate, memory storagecapacity) can be obtained by the master module 12 during a configurationor set-up mode. The master module can employ the bus controller torequest status information (e.g., intermittently or periodically) fromthe respective modules, which status information can be utilized inconjunction with the previously acquired housekeeping information todetermine a relative fullness of the memory in each module. For example,a process running in the processor 32 can cause the bus controller toissue requests for data from one or more of the modular components 14,16, and 18 based on the determined fullness of memory at each of therespective modules. In this way the master module 12 can acquire datafrom modules at different rates to reduce traffic on the bus 26. Therelative fullness thus may vary according to the particular functionseach module is performing, the rate data is sampled and stored and thecapacity of the memory for storing such data at each module.

The processor 32 can also control other functions associated with thesystem 10 such as communication to one or more clients through therespective transceiver 36. The transceiver 36 can be implemented as awired or wireless type of communication device. Those skilled in the artwill understand and appreciate various types of transceivers that can beutilized by the master module 12 to transmit and/or receive data. Forinstance, the processor 32 can transfer data from the memory 34 to theassociated client via the transceiver 36. Alternatively, the client maybe configured to access and download data from selected portions of thememory 34. For example, the client can run an appropriate user interface(not shown) to initiate or terminate or otherwise control one or morefunctions associated with operation of the system 10. The transceiver 36further can be utilized for programming operation of the system 10through an appropriate input/output port.

The master module 12 can also include a clock 40 that is used to controltiming associated with operation of the master module 12 as well as tocontrol the timing associated with data transfers over the bus 26 viathe bus controller 30. The master module 12 can also employ the clock 40to control internal operation of the master module, includingcommunication via the transceiver 36.

The system 10 can further include a data storage module 20 that can beutilized for storing additional data that is transmitted over the bus26. For example, the processor 32 can store data to the data storagemodule 20. Additionally or alternatively, the data storage module 20 canbe implemented as a modular component similar to the other modules12-18, 22 and 24 in the system 10. For example, a module having adesired memory capacity can be connected to the bus as the data storagemodule 20 to increase the overall storage capacity of the system 10.This would allow the data storage function of one or more of the otherthe modular components 12-18, 22 and 24 to be distributed to the datastorage module, further increasing the cost efficiency associated withsuch modules since such modules can be configured with reduced memoryrequirements. A client thus may be able to access and retrieve data fromthe data storage module 20 via the master module (through thetransceiver 36, processor 32 and bus controller 30) and bus 26.

The client may also communicate with the data storage module 20 or othermodules 12-18, 22 and 24 in the system 10 by other communicationdevices. For example, the system 10 can include addition means ofcommunicating to one or more external devices, such as a communicationmodule 22. For example, the communication module 22 can correspond to awireless communication module. The communication module 22, for example,can transmit according to any one of a variety of known wirelessprotocols, such as an 802.11x standard (e.g., WiFi), 802.16x standard(e.g., WiMAX), Bluetooth, cellular communications (e.g., GSM, UMTS andPCS) and the like.

Additionally or alternatively, the system 10 can include a networkinterface module 24 that can be programmed and/or configured to connectto a computer network, such as a local area network (LAN) or a wide areanetwork (WAN) such as including the internet. As one example, thenetwork interface module 24 can be electrically connected to the networkvia a standard network connection. The network interface module 24 thuscan provide an appropriate connection with the desired network. Thus, inthe example of FIG. 1, communications can be implemented over the bus 26via the bus controller 30, over the bus through the network interfacemodule 24 and over the bus via the communication module 22. In this waydata can be transmitted to and received from the system 10 via thenetwork interface module 24.

In the example of FIG. 1, the modular components 14, 16 and 18 can beprogrammed and/or configured based on the requirements of the biometriccondition(s) that is to be measured and/or other functions that are tobe controlled, such as including the administration of a desiredtherapy. Each of the respective components 14, 16 and 18 can includes acommon architecture, which corresponds to circuitry referred to hereinas being embodied in a common data controller (CDC) 42, 44 and 46. Asone example, each of the CDCs 42, 44 and 46 can be a common architecturethat includes a processor or controller and other circuitry that isprogrammed and configured to control operation of the modular componentas well as to facilitate communication to and from the respectivemodular component via the bus 26.

Each of the modular components 14, 16 and 18 also includes modalityspecific circuitry 50, 52 and 54. The modality specific circuitry canvary according to the type of biometric condition data that is to beacquired by a respective module and/or the type of therapy that might bedelivered by the respective module. That is, the modality specificcircuitry 50, 52 and 54 of each of the modules 14, 16 and 18 isprogrammed and/or configured to perform a predetermined biometricfunction (e.g., sensing or therapeutic function—a/k/a modality). Forinstance, one or more of the modules 14, 16 and 18 can be configured toacquire a predetermined type of biometric condition data by sensingbiometric or biological conditions of a patient. Thus, each modularcomponent 14, 16 and 18 can include a particular number of channels foracquiring biometric data from one or more sensors that can be arrangedto detect corresponding biometric or biological conditions.

By way of further example, each of the modality specific circuitry 50,52 and 54 can be adapted to acquire data related to the modalities ofelectromyography (EMG), electrocardiography (ECG),electroencephalography (EEG), plantar pressure, joint angle, pulseoximetry, blood pressure, core body temperature, blood glucose, and thelike. Additionally or alternatively, one or more other modules 14, 16and 18 can be configured to administer a desired therapy (e.g.,electrical or chemical therapies) via corresponding delivery mechanisms.

Thus, each of the modality specific circuitry 50, 52, and 54 includescircuitry operative to provide one or more input signal indicative of abiometric condition. As mentioned above, the input signals can bereceived by the CDC 42, 44, and 46 over a set of channels that can beconfigured according to the particular modality. The signal for eachchannel further can be filtered and processed by the modality specificcircuitry 50, 52 and 54 to provide a digital representation of suchsignal, each of which individually or collectively corresponds to asensed biometric condition of the patient. Alternatively, in othercircumstances, the modality specific circuitry 50, 52 and 54 can providea signal (e.g., feedback signal) associated with a delivery of a therapyto the patient, such as may be in the form of chemical or electricaltherapies.

Each modular component 14, 16, 18 further can be programmed to samplethe input signal(s) for synchronously acquiring biometric data at a dataacquisition rate. Sampling of the input signal can be performed in theanalog or digital domain. The data acquisition rate can be set via theCDC or the modality specific circuitry of a respective modularcomponent. According to one embodiment, each modular component 14, 16,18 can sample a digital representation of the input signal at arespective data acquisition rate. The data acquisition rate for a givenmodular component 14, 16, 18 can be fixed or it can be variable, such asmay vary depending on the operating mode (or state) of the given modularcomponent or the particular monitoring function being performed. Thesampled biometric data can be stored in corresponding memory 60, 62 and64 of each modular component 14, 16 and 18. When the biometric data isstored, a counter (or an index) can be incremented in the memory 60, 62and 64. The counter thus may store an indicator value commensurate withthe amount of memory (e.g., bits or bytes or other units of memory) orlocation in memory that has been written with biometric data.

The master module 12 can retrieve the counter value from one or more ofthe modular components 14, 16 and 18. Since the amount of memory in eachmodular component is known by the master module 12 (e.g., byhousekeeping information retrieved from the modular component), themaster module further can control retrieval of the biometric data fromeach modular component 14, 16 and 18 based on the indication of memoryfullness determined for each respective modular component from thecounter value. Additionally, or alternatively, the master module 12 candetermine or estimate a rate at which the memory is being filled tofurther assist in coordinating retrieval of the biometric data from themodular components 14, 16 and 18. For example, the master module 12 candetermine a change in the counter value for a given modular componentover time (e.g., from a comparison of a preceding counter value of thecounter relative to a subsequent counter value after a plurality ofclock cycles or since a last retrieval of the counter value). The mastermodule 12 can also obtain an indication of the sample rate and anindication of the number active channels to provide a basis forcontrolling retrieval of data from the modular components 14, 16 and 18.Those skilled in the art thus will appreciate that the bus controller 30and instructions executed by the processor 32 in the master module 12can operate as means for controlling retrieval of data from the modularcomponents 14, 16 and 18.

As mentioned above, each of the modular components 12-24 can have a formfactor, which may be a standard or proprietary form factor, which isdimensioned and configured for swappable connection into the system 10.Thus, as the intended use of the system changes, different modularcomponents can be replaced or swapped for other modules so that theaggregate system meets the needs for particular patient. The amount ofmemory for storing biometric data can further vary depending on theintended function of a given module. The master module 12 thus canretrieve data from a given modular component based on the relativefullness determined by the master module for the modular component'memory, such as based on the known configuration and the counter valuefor the respective modular component. The particular combination of dataacquisition and/or therapy administration thus can be tailored on apatient-by-patient basis by interchanging or swapping various modularcomponents, having different modality specific circuitry, into or out ofthe system 10.

Additionally, the respective connections between the modules 12-24 andthe bus are schematically represented as bi-directional arrows. Suchconnections enable data communication from a given one of the respectivemodules to one or more other modules over the bus 26, such as under thecontrol of the bus controller 30 in the master module 12. Additionally,the connections can provide power to each of the respective modules12-24. For instance, a power source 56, such as including a voltageregulator and one or more batteries) can distribute power to each of therespective modules via the bus 26 or other power distribution means.Alternative power systems can be utilized to provide power, such as maybe implemented by separate power connections or in one or more ofmodules 12-24.

FIG. 2 depicts an example of a modular component 100 that can beimplemented according to an aspect of the invention. The modularcomponent 100 includes a CDC 102 that is electrically coupled withmodality specific circuitry 104. The modular component 100 can be selfcontained within a module housing having a preconfigured form factor,which can vary according to system requirements, such as including butnot limited to the examples shown and described herein. The modalityspecific circuitry 104 includes one or more inputs or outputs, indicatedat 106, that can be electrically coupled to respective sensors ortherapy delivery devices (not shown). While for purposes ofsimplification of explanation a single modular component is depicted inFIG. 2, those skilled the art will understand and appreciate that asystem can include any number or one or more modular component based onthe teachings contained herein.

In the example of FIG. 2, the CDC 102 includes data control logic 108that is programmed and configured to control data storage and retrievalfor the modular component 100. For example, the data control logic 108can include data acquisition control 110 that is programmed to controlthe data acquisition rate at which input signals from the modalityspecific circuitry 104 are sampled. For instance, the data acquisitioncontrol 110 can implement a sampling rate based on the type of modularcomponent and its intended purpose, as well as based on a currentoperating mode. The sampling rate may also vary (e.g., it may beincreased or decreased) in response to a biometric condition that isdetected by the modality specific circuitry 104, in response to acondition detected by one or more other module or in response to controlinstructions from a master module (not shown). The data acquisitioncontrol 110 can control the sampling rate based on a clock signalprovided by a clock 112. For instance, the data acquisition control 108can employ a timer, counter or other time basis to periodically samplethe input data from the modality specific circuitry 104 at the definedrate. While the data acquisition control 110 is depicted as beingimplemented in the CDC 102, such functionality could be performed by themodality specific circuitry 104 or through cooperation by both the CDCand the modality specific circuitry.

The CDC 102 also includes memory for storing data and executableinstructions. In the example of FIG. 2, the memory includes a firstmemory structure 114 and a second memory structure 116. Each memorystructure 114 and 116 can be implemented as non-volatile memory,volatile memory or a combination of different memory devices that isconfigured for storing data and executable instructions. The memorystructures 114 and 116 can be different physical memory devices or theymay correspond to separate blocks of memory allocated within a commonmemory device.

In the example of FIG. 2, the first memory structure 114 storeshousekeeping data (e.g., data associated with the module's configurationand operation) and executable instructions for the modular component100. Such housekeeping information can be utilized to determine thehealth or status of the modular component 100, such as by the mastermodule (not shown). As one example, the first memory structure 114 canstore module data 118, counter data 120, control data 122, error data124 and timing data 126. The module data 118 can include moduleidentification information (e.g., model number, serial number and thelike). The module data 118 thus can be utilized (by the master module)to ascertain the intended purpose or function and operating parametersof the modular component 100. The control data 122 can includeinstructions and data that define functions and parameters of the datacontrol logic 108. The error data 124 may include information thatidentifies operating errors for the CDC 102 and/or modality specificcircuitry 104, such as error flags, calibration errors, and timingerrors to name a few. The timing data 126 can be utilized to storetiming information associated with various aspects of operation of theCDC 102, including speed of the clock 112, a local relative time base(e.g., as may be measured from start-up or other predetermined events).

The second memory structure 116 stores biometric data 128 that issampled from the modality specific circuitry 104. The counter data 120of the first memory structure 114 has a value that is indicative of anamount of the biometric data 128 that is stored in the second memorystructure 116. For example, the data in the counter 120 can correspondto an incremental count of the units of memory (e.g., bits or bytes)that are written to in the second memory structure 116. Alternatively oradditionally, the counter data 120 can define a location or offset ofthe data that is written into the second memory structure 116. Forinstance, the counter data 120 can be utilized as an index (or indices)that define a block (or blocks) of biometric data stored in the memorystructure 114. Such an index can be utilized to address correspondingmemory locations in the second memory structure 116 for retrieving thebiometric data 128. Errors associated with the biometric data 128 can beretrieved from the other memory structure 114, such as corresponding tothe error data 124. Such errors can be utilized, for example, todiagnose and/or to repair malfunctioning circuitry and software at themodular component 100, such as by program instructions running on themaster module or another modular component.

The data control logic 108 may also be programmed and configured toperform an access control function 130 (which may include separateaccess control functions) for accessing each of the respective memorystructures 114 and 116. The access control function 130 can also updatethe counter data 120 in response to biometric data being stored in thesecond memory structure 116. The second memory structure 116 can beimplemented as a FIFO data structure, such that a single address orindex value can be utilized to define the biometric data 128 stored insuch memory. For instance, the access control function 130 can incrementthe counter 120 by an amount commensurate with the amount of biometricdata that is stored in the second memory structure 116. The accesscontrol function 130 can thus employ the counter data 120 (or othercontrol instructions) as an index for accessing and retrieving thebiometric data 128 from the second memory structure 116.

As a further example, a master module or another modular component (orprocess running in the system) that is in communication with the modularcomponent 100 through a bus 132 can transmit a request to the modularcomponent. The request, for instance, can be a request for data from thefirst memory structure 114, such as may include any of the data storedtherein, individually or in combination. The request can be provided tothe data control logic 108 via a bus interface 134. In response to therequest, the data control logic 108 employs the access control function130 to retrieve the requested data from the first memory structure 114,which in this example includes at least the counter data 120. The accesscontrol function 130 thus can provide a response, including therequested information, to the requesting module via the bus interface134. The requesting module can also issue a subsequent request forbiometric data from the modular component 100, which again is receivedby the bus interface 134 and processed by the data control logic 108.The request can include a counter value or other address location thatis utilized by the access control function 130 to locate the requestedbiometric data from the second memory structure 116. The counter valueor other location information can be derived from the information sentin a prior response, such as from the module 100 to a master module. Theaccess control function 130 in turn provides a set of one or moreresponses that includes the requested biometric data 128.

The bus interface 134 coordinates the sending of the response data overthe bus 132 back to the requesting module. Additionally, afterretrieving the requested data from the second memory structure 116, theaccess control function 130 can reset the counter data 120 to itsappropriate starting value, which starting value can indicate theabsence of biometric data remaining in the second memory structure 116.It will be appreciated that the master module or other requester canrequest less than all the biometric data 128 from the second memorystructure 116, such as by specifying an offset or location that does notencompass all such biometric data. After the portion of requestedbiometric data is retrieved from the memory structure 116, the accesscontrol function 130 can set the counter 120 to an appropriate value toindicate an offset or location for the remaining biometric data 128 insuch memory.

The modality specific circuitry 104 includes corresponding analogcircuitry 140 depicted as an analog channel 1 to analog channel N, whereN is a positive integer denoting the number of available channels forsending or receiving information and commands. Each analog channel 140is associated with a respective I/O port 106, such as for providingisolation and analog pre-processing the respective input signal. Whilethe modality specific circuitry 104 may have N available channels, it isto be understood that not every channel needs to be an active channel.The particular number of active channels 140 can be set in the moduledata 118 and or the control data 122 in the CDC 102. Those skilled inthe art will understand and appreciate various types of circuitry (e.g.,isolation amplifiers, filters, gain scaling circuits and the like) thatcan be utilized to receive and process signals from appropriate sensorsand provide corresponding input signals for each channel. The particularcircuitry that forms each respective channel 140 and how it may beconfigured in the modality specific circuitry 104 thus can varyaccording to the modality and the biometric conditions intended to bemonitored by the modular apparatus 100. Alternatively, the analogchannels 140 might correspond to output or control circuitry (e.g.,drivers and logic) configured to control delivery of appropriatetherapies, such as a chemical or electrical based therapies. The analogchannels 140 further can provide for isolation between the leads andsensors connected at the ports 106 and the other processing performed bythe modality specific circuitry 104.

Each active analog channel 140 can provide an analog input signal to ananalog-to-digital converter (ADC) 142 that provides correspondingdigital channel representation. The ADC 142 provides the digital channelrepresentation to a processor (e.g., digital signal processor) 144 thatcan be programmed to perform additional signal processing on eachdigital channel representation. The processor 144 can provide theprocessed data to the CDC 102, which can be sampled by the dataacquisition control 110 according to a defined sample rate, such asdescribed above.

FIG. 3 depicts a functional block diagram of a master module 200 thatcan be implemented in a biometric monitoring system 202 according to anaspect of the invention. The biometric monitoring system 202 thus caninclude a data bus 204 over which communication between the mastermodule 200 and one or more modular components 206 can occur. In theexample of FIG. 4, the modular components 206 are indicated at modularcomponent 1, modular component 2 through modular component P, where P isa positive integer denoting the number of modular components in thesystem 202. At least a substantial portion of the modular components 206can include modality specific circuitry that can be programmed andconfigured for monitoring a desired biometric condition as well as fordelivering a therapy to a patient such as described herein.

In the example of FIG. 3, the master module 200 includes a datacontroller 210 that can be programmed and configured to control accessand retrieval of data within the system 202. For instance, the datacontroller 210 can be implemented as computer executable instructionsrunning in a processor for controlling other circuitry including a businterface 212 for sending and receiving requests and responses over thebus 204. The data controller further can control access to associatedmemory 214 that can reside in the master module 200. The memory 214 canbe implemented as volatile or non volatile memory that can include theexecutable instructions for controlling operation of the master moduleas well as for storing data retrieved from one or more of the othermodules 206. It is to be understood and appreciated that while thememory 214 is depicted as residing within the master module 200,additional memory can be implemented into the system 202, such as beingattached to the bus 204 as one of the other respective modularcomponents 206. Thus the amount of memory and storage capability of thesystem 202 is quite extensible.

The data controller 210 also includes a data collection control function216. The data collection control 216 can be a set of one or more programmodules, functions or routines programmed to asynchronously retrievedata from the modules 206. In particular, the data collection module 216includes a memory storage control 218 that controls the overall schemeemployed by the master module 200 for accessing the respective modules206 and retrieving data therefrom. The memory storage control 218 canissue one or more requests to each of the respective modules 206 such asto obtain information from such modules, which can include housekeepingdata, biometric data or a combination of data types. As describedherein, each of the modules or components 206 may be programmed andconfigured to acquire different types of biometric data or to controldelivery of a therapy. Consequently, each of the respective modules mayacquire data at a different rate such that the available memory withineach of the corresponding modules may fill at different respectiverates. Since the master module can know the type of a given module 206and based upon the type of modules the amount of available memory forstoring biometric data, the master module can send requests for certainhousekeeping data from each of the modules based on which it candetermine the relative fullness of the modules. In order to issue theseand other requests, the data collection control 216 includes a requestengine 220 that is configured to employ the bus interface 212 forsending requests over the bus to one or more these modules 206.

As an example, the request engine 220 can packetize a request to anaddress associated with a given module or a broadcast request to the setof modules connected to the bus 204. A request may include data orinstructions calling for certain information, such as housekeepinginformation that may be contained in a memory structure that isdifferent from the memory structure stored in the biometric data for thegiven module 206. As described herein, for example, the request caninclude a request for housekeeping information that includes a countervalue indicative of a location or an index associated with the biometricdata stored in a corresponding memory at each respective module 206.Thus, in response to such request, each modular component 206 can send aresponse with the requested information, including a counter valueindicative a location that can be utilized to ascertain an address orlocation for biometric data in a corresponding memory structure. Theresponse is sent from the modular component 206 over the bus 204.

The bus interface 212 of the data controller 210 provides the responsesto a response engine 222. The response engine 222 handles responsesreceived from the modules such that the data collection control 216 canprocess the responses in a corresponding order. For example, the datacollection control 216 can include a fullness calculation module 224that is programmed to ascertain a relative fullness of the biometricdata in a respective module based on the information contained in aresponse to the corresponding request. As described herein, for example,the response can include a counter value based on which the fullnesscalculator 224 can ascertain the relative fullness of the memorystructure for storing biometric data in each of the respective modularcomponents 206. The relative fullness may be an absolute fullness thatdepends on a predefined capacity of the memory in each module. Therelative fullness calculator may also be programmed to determine a rateat which a respective memory structure is being filled such as can bedetermined based upon other response information including the number ofactive channels at a given modular component and the sampling rate ofdata at a given modular component. Those skilled in the art willunderstand and appreciate various ways and calculations that can beperformed by the fullness calculator 224 based upon housekeeping datareturned in a response from a given modular component.

The data collection control 216 further may include a prioritizationengine 226. The prioritization engine 226 can be programmed toprioritize further requests for biometric data for each of therespective modular components 206. The prioritization can vary accordingto the intended purpose of the biometric monitoring system 202. Theprioritization further may be performed based on the relative fullnessof the memory structure storing the biometric data in each of therespective modular components 206. The prioritization engine may also(or additionally) determine the priority according to the type of eachof the plurality of data acquisition modules and patient specificparameters (e.g., condition of the patient, purpose for the monitoring,as well as other variables associated with the patient). The prioritycan be a weighted priority that is set as a function of the type ofmodule and the amount of data acquired per data acquisition sequence atthe module and based on the patient specific parameters.

The prioritization engine 226 (or other process) can determine if arequest for biometric data is necessary based upon the fullnessdetermined by the fullness calculator 224 for each of the respectivemodular components 206, and if it is determined that a request forbiometric data should be made, the prioritization engine can prioritizethe request for biometric data so that requests are first sent out tohigher priority modular components so that the resulting responses andassociated data are received from such higher priority components. Forexample, certain biometric conditions being monitored may be consideredhigh priority conditions such as pulse rate, brain activity, and thelike where as other condition may be considered lowered priority, suchas monitoring activation of muscular tissue. Thus, those skilled in theart will understand and appreciate various routines and combinations ofinformation that can be utilized to implement appropriate controlsprioritizing requests and responses for biometric data.

As a further example, the memory 214 can store modular configurationdata at 228 and biometric data 230 for each of the respective modularcomponents. For example, during an initialization or calibration phase,the data collection control 216 can send a request to each of thephysical locations or physical addresses at which each of the modularcomponents are connected to the bus 204. Such requests can include dataor instructions calling for return of modular configuration informationfor each modular component, which can result in corresponding responsesbeing sent to the master module 200. The module configurationinformation can in turn be stored as the module configuration data 228at the monster module. The module configuration data 228 thus can beutilized to ascertain the type or function of the given module as wellas the particular configuration thereof. For example, moduleconfiguration data for a given module may include (or the master modulemay derive the following information from the module configurationdata): the memory available for storing biometric data, a level ofpriority associated with the module or component, data sampling rates,the number of active channels and other configuration information thatmay be useful in determining what information is stored in the modularcomponent 206. Thus, the data collection control 216 can determine arelative fullness of memory in each modular component based on theconfiguration data 228 and updated indicator data (e.g., a counter valueas described herein) retrieved from the modular component toasynchronously acquire biometric data from the modular components 206 inthe system 202.

Biometric data received by the response engine 222 further can be storedby the data controller 210 into the memory 214 as the biometric data230. Thus, the memory 214 in the master module can store a set ofbiometric data 230 for each of the respective modular components 206.Additionally, the master module 200 can process data from one or moremodules and store processed sets of data in the memory. Since certainmodules may acquire data at a greater rate than others, the amount ofmemory allocated for a given module can vary according to its intendedpurpose. It would further be appreciated as described herein, that oneor more other modular components 206 can be memory modules for storingadditional biometric data or other data associated with operation of thesystem 202.

As the available memory 214 in the master module 200 or associatedmodular component 206 is nearing its capacity, the master module can beprogrammed to transmit the data or indicate a signal (e.g., audible orvisual or a combination thereof) that can be utilized for triggering adownload of data from the biometric monitoring system 202 to anotherdevice. It should be understood and appreciated that the amount ofmemory available in the system 202 can be sufficient to allow use overan extended period of time for monitoring a number of biometricconditions. The download of information from the biometric monitoringsystem 202 to another device (e.g., a client or service) can beperformed in a variety of ways, such as described herein.

FIG. 4 depicts a perspective view of one example embodiment of a modularsystem 300 that can be constructed in accordance with an aspect of theinvention. The modular system 300 includes a plurality of modularapparatuses 302 configured for performing desired functions such asdescribed herein. For example, by replacing, inserting, swapping a setof one or more modular apparatuses 302, the modular system 300 can beconfigured to operate for acquisition of particular biometric data,control delivery of desired therapy and/or transmit data based on aparticular transmission protocol. As one example, one or the modularapparatuses 302 in the modular system 300 can be adapted to acquire datarelated to electromyography (EMG, e.g., at frequency range 2-500 Hz),another can acquire electrocardiography data (ECG, e.g., at frequencyrange 0.05-100 Hz, and resolution of 24 bits), another may acquireelectroencephalography data (EEG, e.g., frequency range 0.16-100 Hz),while another module may acquire blood pressure data, and other modulesmay acquire data indicative of joint angle, pulse oximetry and the like.Each of the modular apparatuses 302 can be connected to correspondingsensor(s) via an appropriate connector 304.

Each of the modular apparatuses 302 further can include one or morechannels for acquiring and processing input signals indicative ofcorresponding biometric conditions. Each channel of each modularapparatus, for example, provides data that can be sampled at anappropriate data acquisition rate. Due to the different types andfunctions of the modular apparatuses the sampling rates can varysignificantly. The number of channels and sampling rates thus determinethe rate of data storage for each respective modular apparatus 302. Thesampling rates further may change during normal operation depending on avariety of factors such as described herein. For instance, asynchronousdata collection can be implemented across modular apparatuses 302, whileat the same time employing a synchronous clock within each modularapparatus to provide timing on module for local data collectionfunctions. Due to the wide range of potential types of modularapparatuses that can be implemented and corresponding varying rates thatdata may be stored in the memory at such modules, the master module cancollect data asynchronously from each of the modular apparatusesdepending on a relative fullness of the respective memory for suchmodules.

FIG. 5 depicts another embodiment of a modular system 350 that can beimplemented according to an aspect of the invention. In the example ofFIG. 5, the modular system 350 includes a plurality of modularapparatuses 352 spatially distributed along a common communication link(or bus) 354, such as can be implemented as part of a belt or harnessattached to or disposed around the body of a user. While thecommunication link 354 is depicted as a belt in the example of FIG. 6,other types of harnesses (e.g., a chest harness, wrist band, arm band, ahat or the like) could be implemented. Certain modular apparatuses 352can thus be located proximate to predetermined portions of a patient'sbody 356. Data can be communicated with such modular components 352 overa common communication link, or network, wherein all modules on thenetwork communicate via a standard communications protocol. At leastsome of the modular apparatuses 352 include a modular component 358,which can be replaced, inserted or swapped for desired operation. Eachmodular component 358 has a form factor configured according to therequirements and interface provided at the apparatus 352.

In such a distributed system, one or more I/O modules are provided forinterfacing with a process, wherein the outputs derive their control oroutput values in the form of a message from a master controller over thebus 354. For example, a modular component can receive a request orinstruction a processor, via a communications network or a backplanecommunications bus. The desired output value for controlling a deviceassociated with a given biometric condition can be generally sent to theoutput module in a message, such as an I/O message (e.g., a request or aresponse). The modular component that receives such a request messagecan provide a corresponding output response (analog or digital) to thecontrolled process. The modular component can also measure a value of aprocess variable and report the input values to a master controller orpeer modular component over the network or bus 354. The master modulecan control data collection from the modular components to beasynchronous based on the fullness of determined for predeterminedmemory in each of the respective modular components. The input valuesmay be used by the master module for performing control computations.

In view of the structural and functional features described above,certain methods will be better appreciated with reference to FIGS. 6 and7. It is to be understood and appreciated that the illustrated actions,in other embodiments, may occur in different orders or concurrently withother actions. Moreover, not all features illustrated in FIGS. 6 and 7may be required to implement a method according to the subjectinvention. It is to be further understood that the following methodologycan be implemented in hardware (e.g., one or more processors, such as ina computer or computers or in a biomedical device), software (e.g.,stored in a computer readable medium or as executable instructionsrunning on one or more processors), or as a combination of hardware andsoftware.

FIG. 6 depicts a method 400 for asynchronously retrieving data from oneor more modules, such as may form part of a biometric monitoring systemaccording to an aspect of the invention. The method 400 may beimplemented within a master module or other module that may beprogrammed to retrieve or collect biometric data from one or moremodules. As described herein, the biometric data may include sensed datafrom one or more modules as well as feedback and other informationassociated with the control or delivery of a therapy to a patient.

The method begins at 402 such as in conjunction with power-up. Power-upcan include initialization of program parameters and loading operatinginstructions, such as may be programmed to perform a particular task.The task may include a variety of one or more functions associated withmonitoring one or more biometric conditions, delivering therapy to apatient or a combination thereof. The method proceeds to 404 in whichhousekeeping information is requested from one or more modules. Thehousekeeping information can include a variety of information includingbut not limited to module configuration information, moduleidentification information, control information, sampling intervals,number of active channels and the like.

At 406 a determination is made as to whether a response to the request(at 404) is received. If no response is received, the method may returnto 404 for re-requesting such information. Alternatively, a timer ortime up process may be implemented in which a request must receive aresponse within the predetermined time period or the request times out.If the request is timed out, it may be repeated or other action may betaken in the event of an error. If a response is received from 406 themethod proceeds to 408.

At 408, the requested information from the received response is storedin memory. The memory can be local memory, such as in the master moduleor remote memory such as may be located in another module of a biometricmonitoring system. At 410, the fullness of the memory at the module isdetermined based upon the stored information. For example, the fullnessof the memory can be determined based on a counter value (individuallyor in combination with other data) provided in the response received at406 from a remote module. The counter value can indicate a location inmemory at the module relative to knowing the available amount of memoryfor storing such information. The fullness of the memory thus can bederived as an indication of how much biometric data has been stored inthe available memory and/or a determination of how much memory spaceremains for storing biometric data at the respective module. Thefullness determination can be made for one or more of the modules in thebiometric monitoring system based on corresponding responses received at406.

At 412, a determination is made as to whether retrieval of biometricdata is required. If the determination at 412 is negative, indicatingretrieval is not required the method may return to 404. If it isdetermined that retrieval is required the method may proceed to 414. At414, the data collection process from the respective modules can beprioritized. The prioritization can be based on a number of factors,including the relative fullness of memory at the modules, apredetermined relative importance of the type of biometric informationbeing acquired at each of the respective modules as well as othercriteria that may be associated with the intended purpose or function(s)being performed by the biometric monitoring system.

At 416, biometric data can be requested from one or more modules forwhich it has been determined (at 412) that retrieval is required. Therequest can be issued to the address of each module over a correspondingdata bus such as described herein. At 418, responses can be receivedfrom each of the respective modules including the requested biometricdata. The corresponding biometric data can be extracted from thecorresponding responses and stored in memory, such as local memory atthe master module or at some other location at the biometric monitoringsystem. The master module can perform a variety of functions relative tothe stored information which can be utilized to provide usefulinformation about the condition of the patient as well as about thestatus or health of the respective modules. For example, can the mastermodule can compute values based on biometric data received from onemodule or based on an aggregate set of such data received from multiplemodules. From 418, the method proceeds to 420 corresponding to a timerfunction that can be utilized to control the frequency at which thehousekeeping information is requested from the respective modules.Similarly, each of the decisions at 406 and 412 may also return to 404through the timer function 420 to control when housekeeping informationmay be requested from the modules. The timing between requests can bethe same for all modules or it may vary depending on the type orconfiguration of the respective modules. Thus, it will be appreciatedthat the biometric data can be requested asynchronously from the moduleswhere the modules may acquire data synchronously at various ratesaccording to the type of information being acquired by each respectivemodule.

FIG. 7 is a flow diagram depicting a method 450 for certainfunctionality that may be implemented at a given module in a biometricmonitoring system according to an aspect of the invention. In a typicalsystem, each module can thus implement a method similar to the method450, which further may vary in implementation according to the modalityof such module. The method 450 begins at 452 such as may occur atpower-up or upon attachment of a module to a backplane or bus in thebiometric monitoring system. This can include registration with a mastermodule, setting start parameters to their starting values and otherinitialization processes that may be implemented for the module.

At 454, a determination is made as whether a sampling timer has expired.The sampling timer can be set to provide a data acquisition rate for themodality specific circuitry in the given module. The sample rate can befixed for a given module or it may vary depending on an operating modeof the module and a module can have any number of operating modes. Ifthe sample timer has not expired at 454, the sampling can remain idle(e.g., and channel data can be buffered or discarded) during theoperation of the modality specific portion of the module. Once thesampling timer expires, indicating data acquisition is required, themethod proceeds to 456. At 456, the biometric data is sampled from themodality simple circuitry. As described herein, the sample data mayinclude a digital representation of channel data from any number of oneor more channels. The number of channels and amount of data stored foreach channel may vary depending upon the type and configuration of themodule and the purpose of monitoring system. Additionally, the biometricdata may include information associated with the delivery of a giventherapy or other conditions.

At 458, the sampled biometric data is stored in memory of the biometricmonitoring device. This memory can be a different structure form thememory structure employed to store housekeeping information. Thehousekeeping information can include information associated with thehealth of a given module, its configuration and other information suchas described herein. At 460, a counter is updated responsive to thestoring of the biometric data in the memory. The counter can be part ofthe housekeeping information that is utilized to provide an index orother indication relating to the location in the memory where thebiometric data has been stored. As a further example, another processrunning the biometric monitoring system (e.g., at a master module) mayemploy the counter value as an index or address provided in a request(or other message) to retrieve the stored biometric data from the moduleimplementing the method 450. From 460, the method returns to 454 tocontinue the data acquisition process.

Also depicted in FIG. 7 is a basic process for handling a request andproviding responses for data in the given module. This process may runin parallel with or in series with the data acquisition processdescribed at 454 to 460.

At 470, a determination is made as to whether a request is received. Therequest can be received, for example, from a data bus to which the givenmodule is connected through a bus interface. If no request is received,the module may loop at 470. The module may periodically check forrequests via the bus. If a request is received (Yes) the method proceedsfrom 470 to 472. The requested information for example can include arequest for information such as biometric data, housekeeping data, orother information that may be maintained at the given module. The datacan be access from one or more memory structure residing in the givenmodule and, at 474, one or more responses can be provided. For example,certain information may be submitted in a single packet from the moduleto the requester, whereas other information may require multiple packetsto be sent over the bus to complete a given response. Those skilled inthe art will understand and appreciate that the number of packets andmanner in which the data is sent over the bus can vary depending uponthe configuration of the bus architecture and the protocol utilized fordata transmission. From 474, the method can return to 470 for processingadditional requests.

Although the innovation has been shown and described with respect tocertain illustrated aspects, it will be appreciated that equivalentalterations and modifications will occur to others skilled in the artupon the reading and understanding of this specification and the annexeddrawings. In particular regard to the various functions performed by theabove described components (assemblies, devices, circuits, systems,etc.), the terms (including a reference to a “means”) used to describesuch components are intended to correspond, unless otherwise indicated,to any component which performs the specified function of the describedcomponent (e.g., that is functionally equivalent), even though notstructurally equivalent to the disclosed structure, which performs thefunction in the herein illustrated exemplary aspects of the innovation.Furthermore, to the extent that the terms “includes”, “including”,“has”, “having”, and variants thereof are used in either the detaileddescription or the claims, these terms are intended to be inclusive in amanner similar to the term “comprising.”

1. A modular biometric monitoring system comprising: a plurality of dataacquisition modules configured to sample biometric data from at leastone respective input channel at a data acquisition rate, arepresentation of the sampled biometric data being stored in memory ofeach of the plurality of data acquisition modules; and a central controlsystem in communication with each of the plurality of data acquisitionmodules through a bus, the central control system being configured tocollect data asynchronously, via the bus, from the memory of theplurality of data acquisition modules according to a relative fullnessof the memory of the plurality of data acquisition modules.
 2. Thesystem of claim 1, wherein the memory in each of the plurality of dataacquisition modules further comprises: a first memory structure storingbiometric data, and a second memory structure storing housekeeping data,the central control system employing the stored housekeeping dataretrieved from the second memory structure of a given one of theplurality of data acquisition modules to determine the relative fullnessof the memory in the given one of the plurality of data acquisitionmodules.
 3. The system of claim 2, wherein each of the first memorystructure and the second memory structure comprises a respectivefirst-in-first-out (FIFO) data structure.
 4. The system of claim 2,wherein the second memory structure of each of the plurality of dataacquisition modules further comprises a counter that is updated inresponse to storing the representation of the sampled biometric data inthe first memory structure of each of the plurality of data acquisitionmodules.
 5. The system of claim 4, wherein the counter is updated bybeing incremented an amount commensurate with an amount of the sampledbiometric data that is stored in the first memory structure of each ofthe plurality of data acquisition modules, the counter having a valuethat defines at least one of an amount or a location of the biometricdata stored in the first memory structure.
 6. The system of claim 4,wherein the central control system is programmed to determine therelative fullness of the first memory structure in each of the pluralityof data acquisition modules based on the housekeeping data stored in thesecond memory structure including the value of the counter and moduleconfiguration information.
 7. The system of claim 1, wherein the firstmemory structure of each of the plurality of data acquisition moduleshas a capacity that is defined according to a type of the biometric datato be acquired by the respective data acquisition module and the dataacquisition rate thereof.
 8. The system of claim 1, wherein each of theplurality of data acquisition modules further comprises a counter thatis updated in response to storing the representation of the sampledbiometric data in the memory thereof, the central control systemretrieving data indicative of a value of the counter for each of theplurality of data acquisition modules and determining the relativefullness of the memory in each of the plurality of data acquisitionmodules based at least in part on the value of the counter for eachrespective data acquisition module.
 9. The system of claim 8, whereinthe counter of each of the plurality of data acquisition modules isincremented an amount commensurate with an amount of the sampledbiometric data that is stored in the memory thereof for a given samplinginterval, the value of the counter being indicative of an addresslocation of the biometric data that is stored in the memory for each ofthe plurality of data acquisition modules, the central control systembeing programmed to determine the relative fullness of the memory ineach of the plurality of data acquisition modules according to the valueof the counter and a previously defined capacity for each of theplurality of data acquisition modules.
 10. The system of claim 9,wherein the central control system determines the relative fullness ofthe memory in each of the plurality of data acquisition modules based ona change in the value of the counter from a comparison of a precedingcounter value of the counter relative to a subsequent counter value. 11.The system of claim 1, wherein the central control system furthercomprises a prioritization engine that determines a priority thatestablishes at least part of an order from which of the plurality ofdata acquisition modules the biometric data is collected.
 12. The systemof claim 11, wherein the prioritization engine determines the priorityaccording to at least two of: (i) the relative fullness of the memory ofeach of the plurality of data acquisition modules, (ii) a type of eachof the plurality of data acquisition modules and (iii) patient specificparameters.
 13. The system of claim 12, wherein the priority is aweighted priority that is set as a function of the type of module and anamount of data acquired per sequence and the patient specificparameters.
 14. The system of claim 1, wherein each of the plurality ofdata acquisition modules comprises a form factor configured to enablereplacement or swapping of modules into and out of communication withthe bus.
 15. A biometric monitoring system comprising: a plurality ofmodular components configured to sample biometric data received from atleast one respective input channel according to a data acquisition rate,each of the plurality of modular components comprising: a first memorystructure for storing housekeeping information associated with operationof the respective modular component, and a second memory structure forstoring a representation of the sampled biometric data, the housekeepinginformation in the first memory structure being updated in response tostoring the representation of the sampled biometric data in the secondmemory structure; and a master module configured to retrieve dataasynchronously, via a bus to which each of the plurality modularcomponents is connected, from the second memory structure of theplurality modular components according to a relative fullness of thesecond memory structure in each of the plurality modular components asdetermined by the master module based on the updated housekeepinginformation in the plurality of modular components.
 16. The system ofclaim 15, wherein the housekeeping information stored in the firstmemory structure of each of the plurality of modular components furthercomprises a counter having a value that is updated in response tostoring the representation of the sampled biometric data in the firstmemory structure of each of the plurality of modular components.
 17. Thesystem of claim 16, wherein the value of the counter is incremented anamount commensurate with an amount of the sampled biometric data that isstored in the second memory structure of each of the plurality ofmodular components.
 18. The system of claim 16, wherein the mastermodule is programmed to send a request for retrieving the biometric datafrom a given modular component of the plurality of modular components,the request to the given modular component including address datacorresponding to the value of the counter to facilitate access andretrieval of the biometric data from the second memory structure of thegiven modular component.
 19. The system of claim 15, wherein the mastermodule further comprises a prioritization engine that determines apriority for establishing an order from which of the plurality ofmodular components that data is collected by the master module.
 20. Amethod for collecting data from a plurality of modular components, themethod comprising: sampling biometric data for each of the plurality ofmodular components at a substantially synchronous data acquisition rate;storing the sampled biometric data in a first memory structure of eachof the respective plurality of modular components; updating a counter ina second memory structure of each of the plurality of modular componentsin response to the storing of the sampled biometric data; determining afullness of the first memory structure in each of the plurality ofmodular components based at least in part on the updated counter in thesecond memory structure of each respective modular component; andretrieving biometric data from at least one of the plurality of modularcomponents in response to the determined fullness of the first memorystructure in the at least one of the plurality of modular components.